burton14e7
You obviously don't know what you are talking about. Mach is talking about using a this on a sump. If you use a "hook" that when the pump turns off the "hook" will siphon the water out of the tank until the siphon breaks. Then once the pump turns back on, there will be no siphon in the "hook" and you will pump all the water out of the sump, overflow the tank, and flood the room.
I must assume that you thought that he was going to use it for a closed loop--although he clearly talks about a sump and overflow box. In the case of a closed loop, a "hook is fine" because when the pump turns off, the circulation just stops and starts when the pump turns back on. No ability to back siphon.
Please read the posts more carefully, so you don't get someone in trouble.
Just some random thoughts.
ken